That might seem obvious, but timeshare exchanger Interval International provides some specifics in its new resort directory that can help those planning to vacation at times of lower demand — and presumably lower prices. The four highest-demand weeks, by the way, are Nos. 5, 31, 51 and 52 — that’s timeshare speak, which translates in 2009 to the weeks of travel starting Jan. 30-Feb. 1, July 31-Aug. 2, Dec. 18-20 and Dec. 25-27, according to Redweek.com

So what are the times of lowest demand? First, the bad news: Unlike many destinations, Hawaii is truly popular (a “red week,” in timeshare parlance) year-round. Thus its “low season” is really a “less high” season. But even the gentler dips of the Hawaii market can provide noticeable benefits for bargain hunters or solitude seekers. That said, there are eight weeks at the (not-so-deep) bottom of Interval International’s scale: Nos. 19, 37-38, 43, 45-46 and 49-50. For 2009, that’s travel on weeks starting May 8-10; Sept. 11-13 and 18-20; Oct. 23-25, Nov. 6-8 and 13-15; and Dec. 4-6 and 11-18. Bonus for those May-October travelers: generally sunnier skies and warmest weather.

Almost as “slow” — again, in relative terms — as those halcyon days are weeks 16-17 (starting April 17-19 and 24-26), 20-21 (May 15-17 and 22-24), 34-36 (Aug. 21-23 and 28-30, Sept. 4-6), 39 (Sept. 25-27), 41-42 (Oct. 9-11 and 16-18) and 48 (Nov. 27-29), according to Interval International.

The also-rans for peak-period title holder: week 25 (starting June 19-21) and, just behind it, weeks 7 (Feb. 13-15) and 26-27 (June 26-28 and July 3-5). Somehow I don’t think our president-to-be will be making it out for Presidents Day (isn’t every day Presidents Day when you’re president?) or the Fourth of July this year. But Sasha and Malia’s new school gets out the first week of June — that’s week 23 to those keeping track — so there’s plenty of time to schedule another summer trip, peak demand or no. Of course, that may depend on how the economy’s doing — just as it will for the rest of us.